JSON to TypeScript Converter - Generate TS Interfaces Instantly
Front-end applications communicating with REST or GraphQL APIs frequently require TypeScript interface definitions matching backend payloads. Manually writing dozens of nested interfaces is repetitive and error-prone. This utility parses your raw JSON structure and recursively generates clean, well-named TypeScript interfaces adhering to modern TS best practices.
When to Use This Tool
- API Client DTO Modeling: Create accurate response Data Transfer Object (DTO) types directly from Swagger or Postman responses.
- Refactoring JavaScript to TypeScript: Rapidly generate interface definitions for legacy mock data or configuration files.
- Deeply Nested Data Structures: Automatically extract nested sub-objects into standalone, modular child interfaces.
- State Management Typing: Model Redux, Zustand, or TanStack Query store state types straight from initial JSON data.
How to Use
- Paste JSON: Paste your sample JSON object or array into the input editor.
- Specify Root Name: Name your root interface (defaults to RootObject or ApiResponse).
- Review Generated TS: Inspect the generated TypeScript interfaces with inferred primitive and complex types.
- Copy to Project: Copy the clean TS code and paste it directly into your .ts or .types.ts project files.
Input & Output Example
Input:
{
"id": 101,
"title": "Launch DevToolz",
"completed": true,
"author": {
"name": "Alex",
"email": "alex@example.com"
}
}
Output:
export interface Author {
name: string;
email: string;
}
export interface RootObject {
id: number;
title: string;
completed: boolean;
author: Author;
}
Frequently Asked Questions (FAQ)
Q. How does it handle null or undefined values?
A. When a field contains null in the JSON sample, it is typed as any | null. For enterprise codebases, we recommend supplementing with non-null samples to guarantee exact primitive types.
Q. How does it type arrays with mixed object shapes?
A. If array items have identical structures, it extracts a single clean item interface. If items vary, union types or general object types are generated to maintain strict TypeScript compilation safety.
Q. Can it generate "type" aliases instead of "interface"?
A. The default output uses standard TypeScript interfaces for optimal IDE extension performance and contract declaration, which can easily be adapted to type aliases as desired.
Engineering & Privacy Notes
- Pure client-side AST-like recursive parsing with complete confidentiality.
- Supports standard TypeScript 4.x and 5.x syntax without requiring external dependencies.
Related Developer Tools
- JSON Formatter: Beautify and validate the JSON payload before converting to TypeScript.
- JSON Schema Generator: Generate standard JSON Schema validation drafts from raw JSON.
- Diff Checker: Compare API responses across different endpoints or environments.
- JWT Decoder: Inspect and extract payload types from JSON Web Tokens.